Cary V12r with balance unequal when in bias

My Cary V12, when biased with the leds, has an imbalance of output volume. I tried switching input cables, eliminating the preamp and using different input sources, no vinyl. I also swapped tubes from left to right, including the input and current tubes at different times. Everytime the left channel is louder. When I turn down the bias until the balance is equal, all of the left channel leds go unlit. What could be the issue? Thanks all for your input ahead of time.
call cary
Yes, call Cary. They actually have techs available to speak with. Remarkable in this day and age. Having said that, the LEDs are not the most reliable way to bias the amp. If you really want to do it right get a meter. My experience is that the LEDs are not accurate on their own. It's fine in a pinch, but the meter will really allow you to optimize the biasing.
Bias the tubes @ 238mV the LED's just show that the tubes are ok. 1 or 2 degrees of a turn on the adjustments can make a hell of a difference. I have a meter that you can have if you need. I had a V12R and when you bias them right they are a hell of an amp. Best of luck. If you need a tech at Cary, they are there from 1-4 est.